#1 Free Shannon Diversity Index (H’)

Understanding the Shannon Diversity Index (H')

The Shannon Diversity Index (often denoted as H' or H_S) is a popular metric used in ecology to quantify the diversity of species in a community. It accounts for both species richness (the number of different species) and species evenness (the relative abundance of each species).

Formula:

H' = - Σ (pi * ln(pi))

• Σ represents the sum across all species.
• pi is the proportion of individuals belonging to species i (i.e., n_i / N).
• ni is the number of individuals in species i.
• N is the total number of individuals of all species.
• ln is the natural logarithm.
• By convention, if pi = 0 for any species, then pi * ln(pi) = 0.

A higher H' value indicates greater species diversity. The minimum value is 0 (when only one species is present).

Species Richness (S): The total number of different species in the community.

Shannon's Equitability (Evenness - E or J'): Measures how similar the abundances of different species are. It is calculated as:

E = H' / Hmax = H' / ln(S)

• Hmax = ln(S) is the maximum possible diversity for S species (when all species are equally abundant).
• E ranges from 0 to 1, where 1 indicates perfect evenness. If S=1, E is typically considered 1 or undefined.

How to Use:

1. Enter the number of individuals for each species. Use the "Add Species" button to add more input rows.
2. Click "Calculate Diversity" to see the results.